In construction projects, rigid members, such as piles, sheet piles, poles, caissons, or other vertically oriented piles (hereinafter referred to as “piles”) must sometimes be inserted into and/or withdrawn from the earth. Piles may be made out of wood, steel, reinforced and/or prestressed concrete, or other materials. Piles may have a square, rectangular, circular, “H” or other cross-section when viewed through a horizontal cross-section.
Pile insertion and extraction techniques typically involve applying a static force in conjunction with a dynamic, often vibrating force, both forces typically applied at or near the top of a pile. In pile insertion contexts, the static force is commonly provided by the weight of the pile and pile driving equipment while the dynamic force may be provided by i) a diesel, steam, or hydraulic drop hammer which raises a weight and drops it onto the upper end of the pile, ii) a hydraulic, gear, or roller-drive system which presses-in or crowds the pile into the earth, and/or iii) a vibratory system which, for example, may use a pair of balanced, counter-rotating eccentric weights (often obtaining power through a hydraulic connection to a remote power system) to vibrate the pile, which liquefies the earth in contact with the pile and allows the static force to push the pile into the earth (or withdraw it from the earth, in the case of extraction and application of a static lifting force).
Existing pile driving equipment typically includes a caisson-clamp attached to the top of the pile. An example of an existing clamp is shown in FIG. 1. FIG. 1 shows a caisson-beam 1001 and two caisson-clamps 1017 and 1013. The clamps 1017/1013 each comprise an adjustment mechanism 1005, a fixed jaw face 1011, an adjustable jaw face 1009, a pile guide 1007, and caisson-beam track 1015. In use, the distance between two such caisson-clamps is adjusted by sliding the clamps along the caisson-beam through the caisson-beam tracks. The distance between the caisson-clamps is first roughly selected to allow the fixed jaw face 1011 and adjustable jaw face 1009 to be lowered onto a pile. The adjustable jaw face 1009 may have a roughly flat face, as shown in the detail view in FIG. 1, while the fixed jaw face 1011 may have a convex curve, generally with a tighter arc angle than the interior of the pile into which the caisson-clamps are to be lowered. The adjustable jaw face 1009 may be tightened (via the adjustment mechanism 1005) against the outside of the pile, causing the clamp to adjust its position relative to the pile 1000 and causing the fixed jaw face 1011 to tighten against the inside of the pile 1000. The top of the pile 1000 is then pinched at two locations 1019 and 1021 by the jaw faces. Wedges 1020 may then be tightened to secure the position of the caisson-clamps 1013/1017 on the caisson-beam 1001.
As shown in FIG. 1, two caisson-clamps are shown at the approximate center of a caisson-beam, with the caisson-clamps having a left- and right-sided orientation as viewed in the figure (so that the adjustable jaw side of both clamps is on the exterior of the pile). Two caisson-clamps are also shown at opposite ends of the caisson-beam, caisson-clamps 1013 and 1017, both of which clamps are shown with a left-sided orientation. In use, caisson-clamp 1017 would be removed from the caisson-beam, rotated 180 degrees, and re-inserted onto the caisson-beam with a right-sided orientation.
The existing prior-art caisson-clamps require placement and replacement of four jaw faces and often require clamps and/or jaw faces sized to specific piles or narrow ranges of piles. Existing caisson-clamps often require that the pile be machined, welded, cut, ground, or otherwise modified prior to and/or after insertion or extraction, procedures which take time, expertise, and which may add cost, time, and complexity to a pile insertion and/or extraction procedure as well as to utilization of the pile after the insertion and/or extraction procedure. The pile used in prior-art systems must be hollow to accommodate the caisson-clamps or must be modified to accommodate the caisson-clamps. Needed is a pile clamp which addresses these shortcomings.